Novel Metal-Polymer Nanocomposites as Heat and Pressure Sensitive Materials

During the last decade considerable work has been carried out to understand nanomaterials and their assemblies. Using metal nanoparticles, it is possible to synthesize some interesting nano-composites. Nanocomposites are new generation of multifunctional materials which have attracted great interest in the last few years. They are novel materials which combine the advantages of different constituting materials. Metal nanoparticles - polymer composite materials are of wide interest because of their potential in optical, electrical and biomedical applications [1-3]. The enhancement of electrical conductivity of the insulating polymers is observed by using different conductive and semiconductive fillers. We present the fabrication and characterization of metal particles- polymer nanocomposites as well as composites of microparticles with some polymers, viz. gold [4] and silver nanoparticles - polymethylmethacrylate (PMMA) nanocomposites and zinc-polydimethylsiloxane (PDMS) with different amount of particle filling. The electrical transport properties of gold and silver-PMMA nanocomposites have been investigated in a wide temperature range of 70 K to 300K. Gold - PMMA nanocomposites were fabricated also with a photoreduction method using UV irradiation [5]. Mechanism of gold nanoparticles formation under UV irradiation in the polymer matrix and the morphology of the particles will be presented. In another experiment we incorporated copper and zinc particles in polydimethylsiloxane and investigated their piezoresistive response [6]. The piezoresistive behavior of the Zn-PDMS composites under uniaxial pressure shows the resistivity changes by more than seven orders of magnitude around 4MPa pressure. We found that the piezoresistive behavior of the Zn-PDMS composites can be explained in the framework of electron tunneling between the metal particles